In-conduit turbines and hydroelectric power systems

ABSTRACT

Inventive systems (e.g., turbines) for harnessing hydroelectric energy are described. The turbines include: (1) a central longitudinal shaft configured to mount and to rotate on a central axis perpendicular to a direction of fluid flow; (2) a plurality of substantially circularly arcing blades designed to couple to the shaft, each of the substantially circularly arcing blades having defined at one end one or more blade apertures; and (3) a fastening sub-assembly including fasteners, the fastening sub-assembly used for coupling the circularly arcing blades to the shaft.

FIELD OF THE INVENTION

The present invention relates generally to turbine assemblies useful forharnessing hydroelectric energy. More particularly, the presentinvention relates to improved in-conduit turbines and hydroelectricpower systems.

BACKGROUND OF THE INVENTION

Hydroelectric energy refers to the generation of energy from the flow,current, or velocity of water. This type of energy is different fromhydroenergy, which traditionally refers to power generated using dams(impoundment or run-of-river). Because hydroelectric energy relies onthe velocity of water, these energy systems can be placed into sourcesof flowing water with minimal infrastructure or environmental impacts.As a result, hydroelectric power is considered cutting-edge waterpower.

To harness hydroelectric energy, turbines typically operate in rivers,oceans and tidal settings. By way of example, in rivers, turbines can beinstalled for applications that harness energy from such settings asin-stream, free-flow, open-river or hydroelectric run-of-river. As otherexamples, in ocean and tidal settings, turbines harness ocean power andtidal power, respectively.

These turbines may be loaded onto a barge, which is well equipped withcranes to facilitate the raising and lowering of individual turbines andpower generating units that accompany them. In other examples, theseturbines may be integrated into an in-conduit hydroelectric powergenerator.

Unfortunately, previous designs of hydroelectric power generators sufferfrom certain drawbacks. By way of example, previous designs employ amechanism of attaching turbine blades to other components of a turbinewith fasteners that results in a relatively higher amount of force beingplaced on the fasteners. This typically results in relatively poor loaddistribution throughout the blade-attachment mechanism. Further, givensuch limitations, prior designs are unable to use a wider variety ofmaterials to construct certain components of a hydroelectric powergenerator.

What is therefore needed are designs and assembly methods for fasteningblades to other components of a turbine that provide less stress on thefastening mechanism, stabilize a turbine during rotation, and allow fora wider variety of materials to be used in constructing certaincomponents of a turbine used in a hydroelectric generators.

SUMMARY OF THE INVENTION

In view of the foregoing, in one aspect, the present invention providesnovel systems and methods for increasing efficiency and power output ofin-conduit hydroelectric power systems and turbines.

In one aspect the present invention discloses a turbine. The turbineincludes: (1) a central longitudinal shaft configured to rotate on acentral axis perpendicular to a direction of fluid flow; (2) a pluralityof substantially circularly arcing blades designed to be coupled to theshaft, and each of the substantially circularly arcing blades havingdefined at one end one or more blade apertures; (3) a fasteningsub-assembly including fasteners and the fastening sub-assembly used forcoupling the substantially circularly arcing blades to the shaft; and(4) wherein, in an assembled configuration of the turbine, a sweep ofthe arcing blades defines a substantially spherical shape when thearcing blades rotate with the shaft, each end of the substantiallycircularly arcing blades extends outwardly from the shaft such that aplane defined by each of the blades is not parallel to the central axisand when the fastening sub-assembly couples the arcing blades to theshaft, the fasteners pass through one or more blade apertures. In oneembodiment of the present invention, each end of the substantiallycircularly arcing blades extends outwardly from the shaft such that aplane defined by each of the blades is not parallel to the central axis.Preferably, the turbine includes another fastening sub-assembly, suchthat the fastening sub-assembly and another fastening sub-assembly aredesigned to be disposed at opposite ends of the shaft and coupleopposite ends of the substantially circularly arcing blades to theshaft. More preferably, each of the fastening sub-assembly and anotherfastening sub-assembly includes a hub plate having defined therein hubapertures such that the fasteners are designed to pass through the hubapertures. Even more preferably, each of the fastening sub-assembly andanother fastening sub-assembly includes an auxiliary plate havingdefined therein auxiliary apertures such that the fasteners are designedto pass through the auxiliary apertures.

In preferred embodiments of the present invention, in an assembledconfiguration of the turbine, each of opposite ends of the substantiallycircularly arcing blades is sandwiched between the corresponding hubplate and the corresponding auxiliary plate, and a first portion of eachof the fasteners is on one side of each of the substantially circularlyarcing blades, and a second portion of each of the fasteners is on theother side of each of the substantially circularly arcing blades. In anassembled configuration of the turbine, corresponding ones of the bladeapertures, the hub apertures and the auxiliary apertures may align suchthat the fasteners fasten corresponding ones of the hub plate, theauxiliary plate and the substantially circularly arcing blades. Theturbine may further include opposing shaft couplers for securelyaffixing each of the fastening sub-assembly and another fasteningsub-assembly to the shaft.

Each of the substantially circularly arcing blades may include, along asubstantial length, an airfoil cross-section. In certain embodiments,the substantially circularly arcing blades define a nominal soliditythat is between about 15% and about 30%. Preferably, an angle betweenthe plane defined by each of the substantially circularly arcing bladesand the central axis of the shaft is a value between about 10 degreesand about 45 degrees. The substantially circularly arcing blades may bemade from composite, plastic or metal.

In another aspect, the present invention discloses a power generatingsystem. The power generating system includes: (1) a turbine, comprising(a) a central longitudinal shaft configured to rotate on a central axisperpendicular to a direction of fluid flow, (b) a plurality ofsubstantially circularly arcing blades designed to be coupled with theshaft, and each of the substantially circularly arcing blades havingdefined at one end one or more blade apertures, (c) a fasteningsub-assembly, including fasteners and the fastening subassembly used forcoupling the substantially circularly arcing blades to the shaft, and(d) wherein, in an assembled configuration of the turbine, a sweep ofthe arcing blades defines a substantially spherical shape when thearcing blades rotate with the shaft, and when the fastening sub-assemblycouples the arcing blades to the shaft, the fasteners pass through theone or more blade apertures; and (2) a generator capable of beingoperatively coupled to the shaft of the turbine and, during anoperational state of the power generating system, the generatorgenerates power from rotation of the turbine caused by a fluid impingingon the blades. In one embodiment of the present invention, each end ofthe substantially circularly arcing blades extends outwardly from theshaft such that a plane defined by each of the blades is not parallel tothe central axis.

In preferred embodiments of the present invention, the power generatingsystem further includes a turbine further comprising another fasteningsub-assembly, such that the fastening sub-assembly and another fasteningsub-assembly are designed to be disposed at opposite ends of the shaftand couple opposite ends of the substantially circularly arcing bladesto the shaft. Each of the fastening sub-assembly and another fasteningsub-assembly may include a hub plate having defined therein hubapertures such that the fasteners are designed to pass through the hubapertures. Each of the fastening sub-assembly and another fasteningsub-assembly may include an auxiliary plate having defined thereinauxiliary apertures such that the fasteners are designed to pass throughthe auxiliary apertures.

In preferred embodiments of the inventive power generating system, eachof opposite ends of the substantially circularly arcing blades issandwiched between the corresponding hub plate and the correspondingauxiliary plate, in an assembled configuration of the turbine.Furthermore, in this embodiment, a first portion of each of thefasteners is on one side of each of the substantially circularly arcingblades, and a second portion of each of the fasteners is on the otherside of each of the substantially circularly arcing blades. Preferably,in an assembled configuration of the turbine, corresponding ones of theblade apertures, the hub apertures and the auxiliary apertures alignsuch that the fasteners fasten corresponding ones of the hub plate, theauxiliary plate and the substantially circularly arcing blades.

In yet another aspect, the present invention discloses an electric powergenerating system. The electric power generating system includes: (1) aconduit for conveying a fluid; (2) a turbine disposed inside theconduit, comprising (a) a central longitudinal shaft configured torotate on a central axis perpendicular to a direction of fluid flow, (b)a plurality of substantially circularly arcing blades designed to becoupled with the shaft, and each of the substantially circularly arcingblades having defined at one end one or more blade apertures, (c) afastening sub-assembly including fasteners and the fastening subassemblyused for coupling the substantially circularly arcing blades to theshaft; and (d) wherein, in an assembled configuration of the turbine, asweep of the substantially circularly arcing blades defines asubstantially spherical shape when the substantially circularly arcingblades rotate with the shaft, and when the fastening sub-assemblycouples the substantially circularly arcing blades to the shaft, thefasteners pass through the one or more blade apertures; and (3) agenerator capable of being operatively coupled to the shaft of theturbine and, during an operational state of the power generating system,the generator generates power from rotation of the turbine caused by afluid impinging on the blades. In one embodiment of the presentinvention, each end of the substantially circularly arcing bladesextends outwardly from the shaft such that a plane defined by each ofthe blades is not parallel to the central axis. Preferably, the diameterof a cross section of the conduit is a value that is between about 12inches and about 144 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of an electric power generatingsystem, according to one preferred embodiment of the present invention,for generating power.

FIG. 2 is an exploded, perspective view of a turbine assembly, accordingto one preferred embodiment of the present invention, shown as part ofthe electric power generating system of FIG. 1.

FIG. 3 is a side-sectional view of an electric power generating system,according to one embodiment of the present invention, for generatingpower.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art that the presentinvention is practiced without limitation to some or all of thesespecific details. In other instances, well-known process steps have notbeen described in detail in order to not unnecessarily obscure theinvention.

FIG. 1 is an exploded, perspective view of an electric power generatingsystem 100, according to one embodiment of the present invention, forgenerating power. When assembled, electric power generating system 100includes a spherical turbine assembly 116 disposed inside a conduit 102.In an assembled configuration, a generator-plate assembly 118 ispositioned atop a flange 114 of conduit 102. Generator-plate assembly118 includes a circular attachment plate 122, which is disposed below agenerator sub-assembly 120. Circular attachment plate 122 is attached toflange 114, which is resting on a protruding top portion of conduit 102.As shown in FIG. 1, circular attachment plate 122 uses a three-vanedcylindrical spacer 126 to hold inventive turbine assembly 116 in placebelow a cover plate 124. Fluid flow through conduit 102 causes rotationof turbine assembly 116, which uses components of generator sub-assembly120 to convert mechanical energy to electrical energy.

Conduit 102 is equipped with flanges 104 a and 104 b disposed on eachend. Flanges 104 a and 104 b may be used to bolt upstream or downstreamadditional conduits, including those that are fitted with additionalelectric power generating systems (not shown to simplify illustration).A cross section of conduit 102 preferably has a diameter that is a valuebetween about 12 inches and about 144 inches. A cross section of conduit102 is preferably circular, though in alternate embodiments of thepresent invention, it may be of an oval shape. Conduit 102 and itscomponents may be composed of any rigid material that does not absorbwater or any other fluid used to generate energy by fluid flow.

At a bottom end, conduit 102 has defined therein an aperture 106 capableof receiving and having pass therethrough a shaft 117 of turbineassembly 116. A mounting plate 110 is attached (preferably by welding orsome other conventional method known to those skilled in the art) to theoutside surface of a bottom end of conduit 102. Though not shown,mounting plate 110 also has defined therein an aperture, which alignswith aperture 106. In preferred embodiments of the present invention,mounting plate 110 is disposed below a shim (not shown to simplifyillustration) having an exterior planar surface and an inner cylindricalsurface for mating with the external cylindrical surface of conduit 102.

A first bearing 112, capable of receiving and having pass therethroughshaft 117 of turbine assembly 116, is attached to mounting plate 110. Ata bottom end, shaft 117 is preferably grooved and capped with a snapring (not shown to simplify illustration) or the like capable ofstabilizing shaft 117.

At a top end, conduit 102 has defined therein an aperture 108 belowflange 114 that is large enough to allow turbine assembly 116 (describedin further detail below with reference to FIG. 2) to pass through and beplaced inside conduit 102. In an assembled configuration of electricalpower generating system 100, cover plate 124 covers aperture 108. It isimportant to note, however, that cover plate 124 is removable fromconduit 102 and thus provides a means by which turbine assembly 116 maybe installed inside or removed from conduit 102 for assembly ordisassembly. As shown in FIG. 1, cover plate 124 also has definedtherein an aperture large enough to allow shaft 117 of turbine assembly116 to pass therethrough. During operation of electric power generatingsystem 100, when fluid flows through conduit 102, cover plate 124provides a contiguous round surface to facilitate fluid flow throughconduit 102, thereby avoiding turbulence or other fluid flow disruption.It is important to note, however, that cover plate 124 is an optionalfeature of the present invention.

Generator-plate assembly 118 is disposed above conduit 102. At a bottomend, generator-plate assembly 118 includes three-vaned cylindricalspacer 126 disposed below circular attachment plate 122. Circularattachment plate 122 includes a circular plate 132 attached at a bottomend, preferably by bolting, to an annular seal 128. Using the sameattachment mechanism, circular attachment plate 122 attaches to circularflange 114. In this configuration, a top end of three-vaned cylindricalspacer 126 is connected to a bottom end of circular plate 132,preferably by bolting, and a bottom end of three-vaned cylindricalspacer 126 is connected to circular attachment plate 122, preferably bywelding, holding cover plate 124 in place atop turbine assembly 116during operation of the inventive electrical power generating systems.Alternate embodiments of the present invention include a spacer with anyplurality of shapes or number of vanes capable of coupling circularattachment plate 122 to conduit 102 and holding cover plate 124 inplace.

At a top end, circular plate 132 has defined therein a circular plateaperture 134 capable of receiving and having pass therethrough a top endof shaft 117 of turbine assembly 116. Disposed above circular plateaperture 134 is a second mounting block 136, having defined therein anaperture capable of receiving and having pass therethrough a top end ofshaft 117 of turbine assembly 116 for smooth rotation of the shaft.

The components of circular attachment plate 122 are preferably made fromany rigid material known to those skilled in the art, except annularseal 128 is preferably made from a compressible material, such as anelastomer (e.g., rubber), capable of sealing the attachment betweencircular plate 132 and flange 114. In certain embodiments of the presentinvention, circular plate 132 is of a relatively flat configuration, asshown in FIG. 1. In such embodiments, circular plate is made fromrelatively thicker material, and may therefore be relatively difficultto handle. In alternate embodiments of the present invention, however,circular plate 132 may be of a relatively spherical, downwardly concaveconfiguration. Those skilled in the art will recognize that in suchembodiments, the curvature of a downward concave configuration ofcircular plate 132 allows it to be made from relatively thin material,thus providing the advantage of being significantly easier to handle.Furthermore, using a downward concave configuration of circular plate132 provides the advantage of a shortened length or vertical span ofshaft 117 of turbine 116.

At a top end of circular attachment plate 122, a second bearing 138,capable of attaching to and having pass therethrough an upper end ofshaft 117, attaches to second mounting block 136. Thus, when electricpower generating system 100 is in an assembled state, a lower end ofshaft 117 passes through a first bearing 112, and an upper end of shaft116 passes through a second bearing 138. In preferred embodiments of thepresent invention, first and second bearings 112 and 138 includespherical roller bearings producing only rolling friction for smoothrotation of shaft 117 during rotation of turbine assembly 116. Inalternate embodiments of the present invention, first and secondbearings 112 and 138 use sleeve bearings or other sliding frictionarrangements, facilitating rotation of the inventive turbine assembly116 during operation. The present invention recognizes that bearings 112and 138 enable electric power generating system 100 to operate safely,reliably and durably to produce electricity with a fluid flow ratethrough conduit 102 of as little as between about 3 feet/second (“fps”)and about 4 fps.

Generator sub-assembly 120 is disposed above circular attachment plate122. Generator sub-assembly 120 includes an annular spacer 140, ashaft-coupling device 144, an annular rim 142 attached to a firstmechanical lift tab 146 a, and a generator 148 attached to a secondmechanical lift tab 146 b. At a bottom end of generator 148 is an uppershaft 149 capable of being connected to shaft-coupling device 144.

Annular rim 142 includes a series of fasteners, preferably bolts or thelike, that extend downward around an outer periphery. These fastenersare received by corresponding apertures, defined on a top end of annularspacer 140. Similarly, annular spacer 140 includes at a bottom end aseries of fasteners, preferably bolts or the like, that extend downwardaround an outer periphery. These fasteners are received by correspondingapertures of circular plate 132, thus coupling generator sub-assembly120 to the other components of the inventive electric power generatingsystems.

Housed within annular spacer 140 is shaft-coupling device 144, capableof coupling generator 148 to turbine assembly 116. Shaft-coupling device144 attaches at a bottom end to a top end of shaft 117, and at a top endto a bottom end of generator shaft 149. Generator shaft 149 is coupledto a bottom end of generator 148. When an inventive electric powergenerating system is in operation, shaft-coupling device 144 transferstorque from rotation of turbine 116 to generator 148. Generator 148 isany generator capable of converting mechanical energy received fromoperation of turbine assembly 116 to electrical energy. Generator 148may produce direct or alternating current and single-phase or 3-phase,synchronized 120 VAC or 240 VAC, or the like, and/or may be convertedfrom one to the other, depending upon the power grid requirements.

A first mechanical lift tab 146 a is attached to annular rim 142, and asecond mechanical lift tab 146 b is attached to generator 148. Thoseskilled in the art will recognize that when the inventive electric powergenerating system 100 is in an assembled state (shown below in FIG. 3),mechanical-lift tabs 146 a and 146 b provide convenient tabs for liftingall or part of the assembled electric power generation components duringassembly or disassembly.

FIG. 2 is a perspective, exploded view of turbine assembly 216,according to one preferred embodiment of the present invention. Tofacilitate discussion, FIG. 2 shows some of the major components ofturbine assembly 116 shown in FIG. 1. Turbine assembly 216 includesblades 250, which are each attached at a blade end 252 to a hub plate254 with a fastening sub-assembly 232. Fastening sub-assembly 232includes an auxiliary plate 256, fasteners 258 and immobilizers 260.Though not shown in FIG. 2, when assembled, the inventive turbineassembly includes a central longitudinal shaft (e.g., shaft 117 ofFIG. 1) configured to rotate on a central axis perpendicular to adirection of fluid flow through a conduit (e.g., conduit 102 of FIG. 1).In preferred embodiments of the present invention, like components ofturbine assembly 216 (e.g., blade ends, hub plate, auxiliary plate,fasteners and immobilizers) are disposed at opposite ends of a shaftsuch that blades 250 are coupled to the shaft at a top and a bottom end(of the shaft). In this manner, each end of a blade may be coupled tothe shaft.

Blades 250 are of a substantially circularly arcing configuration. Inpreferred embodiments of the present invention, when the inventiveturbine assembly is in operation, blades 250 preferably sweep aspherical area. In alternate embodiments, blades 250 sweep anon-spherical, or somewhat oval, area (e.g., a blade-swept area that istaller than it is wide, or is wider than it is tall) when the inventiveturbine assembly is in operation. Preferably, blades 250 are of aconstant radius, though in alternate embodiments of the presentinvention, blades 250 are of a variable radius.

Blades 250 include a blade end 252 with one more blade apertures, eachcapable of receiving a fastener 258 therethrough. In certain embodimentsof the present invention, blade end 252 is fabricated as part of eachblade 250. In alternate embodiments, blade end 252 is fabricatedseparately and attached to each blade 250 by any method known to thoseskilled in the art. In such embodiments, blade end 252 may be composedof a different material or materials than blade 250.

When inventive turbine assembly 216 is in an assembled state, blades 250are spaced, preferably evenly, around a shaft. In preferred embodimentsof the present invention, the angle between the plane defined by each ofblades 250 and the central axis of a shaft is a value that is betweenabout 5 degrees and about 45 degrees, more preferably a value that isbetween about 10 degrees and about 30 degrees. In certain embodiments ofthe present invention, blades 250 extend such that a plane defined bythem is not parallel to a shaft.

Preferably, each end of blades 250 extends outwardly from a shaft.According to preferred embodiments of the present invention, sufficientclearance around the blade-swept area of blades 250 is provided to avoidundue compression of fluid at turbine-sweep boundaries.

In preferred embodiments of the present invention, blades 250 arecharacterized along a substantial length by an airfoil cross-section. Incertain of these preferred embodiments of the present invention, theairfoil cross-section conforms to the recognized NACA 20 standard, whichis well known to those skilled in the art. Regardless of the airfoilcross-section shape, the airfoil cross-sections are selected to providethe inventive turbines with improved hydrodynamics and efficiency forgenerating power.

While FIG. 2 shows a turbine assembly capable of employing fivesubstantially circularly arcing blades 250, the present inventioncontemplates use of any number of plurality of blades. Blades 250 arecomposed of any rigid material known to those skilled in the art. Inpreferred embodiments of the present invention, blades are made from atleast one material selected from a group consisting of aluminum, asuitable composite (e.g., a fiberglass composite or a carbon fibercomposite), and a suitable homogenous or reinforced plastic material.

It is noteworthy that the present invention contemplates turbine shapesthat are slightly or somewhat oval in cross-section. In suchembodiments, the inventive turbine assemblies used in an electric powergenerating system may employ a conduit that has a correspondingly ovalcross-section.

Fastening sub-assembly 232 (described below in more detail) attachesblades 250 via blade ends 252 to hub plate 254. Hub plate 254 ispreferably of a relatively flat configuration and includes a receivingportion 262 for attachment of each of blade ends 252. As shown in FIG.2, each receiving portion 262 of hub plate is preferably indented suchthat when blade end 252 is attached to hub plate 254, separate tongueportions 264 of hub plate 254 align blade end 252 laterally on eachside. Alternate embodiments of the present invention, however, include areceiving portion for each blade end 252 that is not indented and thatdoes not include tongue portions 264.

Hub plate 254 also has defined at or near its center an aperture capableof receiving and having pass therethrough a shaft (e.g., shaft 117 ofFIG. 1). Though not shown, attached at a bottom end to hub plate 254 isa split shaft coupler capable of receiving a shaft (e.g., shaft 117 ofFIG. 1) and transferring torque from hub plate 254 to that shaft duringrotation of turbine assembly 216. The split shaft coupler alsostabilizes the shaft during operation of turbine assembly 216.Preferably, at a bottom end of turbine assembly 216, a correspondingsplit shaft coupler similarly attaches to a top end of bottom hub plateto stabilize the shaft in a like manner.

As shown in FIG. 2, auxiliary plate 256, as well as blade end 252 andhub plate 254, have defined therein corresponding apertures capable ofreceiving fasteners 258 when the different apertures are aligned. In anassembled state of auxiliary plate 256, blade end 252 and hub plate 254,blade end 252 is sandwiched between auxiliary plate 256 and hub plate254. Furthermore, in this configuration, fasteners 258 pass through thecorresponding apertures such that a first portion of each fastener 258is on one side of each blade end 252 and a second portion of eachfastener 258 is on the other side of each blade end 252. Each fastener258 is secured at a bottom end by its associated immobilizer 260.Fasteners 258 and immobilizers 260 contemplated by the present inventioninclude any such mechanism known to those skilled in the art to fasten ablade to a hub plate, including by way of example, bolts and nuts, orscrews and washers.

Associated fasteners 258 and immobilizers 260 are designed to facilitateattachment of blades 250 to hub plate 254. In this embodiment, fastenerspass through corresponding apertures of blade end 252, hub plate 254 andauxiliary plate 256. Although preferred embodiments of the presentinvention contemplate use of auxiliary plate 256 to stabilize attachmentof blades 250, alternate embodiments of the present invention do notcontemplate use of auxiliary plate 256.

The fastening sub-assembly configuration employed by the presentinvention realizes certain advantages over previous designs. Forexample, previous designs utilize fasteners that attach to blades in anorientation perpendicular to a turbine's axis of rotation, typically byfastening into an end edge of a blade without passing through the blade.By contrast, the present invention employs a mechanism whereby afastener will pass through a blade in a configuration that is relativelyparallel to a turbine's axis of rotation. As a result, the presentinvention provides significantly lower blade to hub plate stresses, suchthat less force is directly applied to the fasteners. These fastenersserve indirectly to create substantial friction between blade ends 252and hub plate 254, such that loads are directly transferred from bladeends 252 to hub plate 254. In other words, the present inventionrealizes an increase in shear loads and a decrease in tension loads whencompared to previous designs, resulting in better load distributionthroughout the blade attachment sub-assembly. Not only does this providea design that stabilizes the inventive turbine assembly during rotation,it also allows for a greater versatility in blade materials. Inparticular, certain desired composite materials (e.g., a fiberglasscomposite or a carbon fiber composite), which could not be used tomanufacture previous turbine assembly designs, represent preferredembodiments when manufacturing inventive turbine assemblies.

FIG. 3 is a side-sectional view of an electric power generating system300, according to one embodiment of the present invention, whichgenerates power from fluid flow through in-conduit turbine assembly 316.FIG. 3 is substantially similar to the electric power generating systemof FIG. 1, except FIG. 3 shows the inventive system in an assembledconfiguration. Electric power generating system 300 includes a generatorcap assembly 318 coupled to turbine assembly 316, which is disposedwithin conduit 302. Turbine assembly 316 is substantially similar toturbine assembly 116 and 216 of FIGS. 1 and 2, respectively. Turbineassembly 316 includes a shaft 317 disposed substantially perpendicularto the direction of fluid flow inside conduit 302, which has a flange304 disposed on each end (although only one end is visible in the sideview of FIG. 3).

Generator-cap assembly 318 is disposed above turbine assembly 316 andconduit 302. Specifically, a flat surface is formed by a cover plate322, which is coupled to flange 314 of conduit 302. At the end of shaft317, a bearing 338 is attached, which is disposed beneath a generator348. Generator 348 mounts to and rotates with the distal end of shaft317. As shown in FIG. 3, an annular rim (having attached thereto firstmechanical lift tab 346 a) and generator 348 (having attached theretosecond mechanical lift tab 346 b) are coupled to each other and disposedabove a shaft-coupling device 344. Those skilled in the art willrecognize that first and second mechanical lift tabs 346 a and 346 bprovide convenient tabs for lifting all or part of the assembledelectric power generating system components during assembly ordisassembly.

Two or more inventive electric power generating systems may be installedat defined intervals (in series) within and along a water-conveyingconduit for increased power generation. To this end, flange 304 may beused to couple to upstream or downstream conduits including additionalelectric power generating systems (not shown to simplify illustration).Likewise, those skilled in the art will recognize parallel arrangementsof two or more hydro-electric power generation systems may be installedwithin branches of a water-conveying conduit for increasing powergeneration.

Although illustrative embodiments of this invention have been shown anddescribed, other modifications, changes and substitutions are intended.Accordingly, it is appropriate that the appended claims be construedbroadly and in a manner consistent with the scope of the disclosure, asset forth in the following claims.

What is claimed is:
 1. A turbine comprising: a central longitudinalshaft configured to rotate on a central axis perpendicular to adirection of fluid flow; a plurality of substantially circularly arcingblades designed to be coupled to said shaft, and each of saidsubstantially circularly arcing blades having defined at one end one ormore blade apertures; a fastening sub-assembly including fasteners andsaid fastening sub-assembly used for coupling said substantiallycircularly arcing blades to said shaft; and wherein, in an assembledconfiguration of said turbine, a sweep of said arcing blades defines asubstantially spherical shape when said arcing blades rotate with saidshaft, and when said fastening sub-assembly couples said arcing bladesto said shaft, said fasteners pass through said one or more bladeapertures.
 2. The turbine of claim 1, wherein each end of saidsubstantially circularly arcing blades extends outwardly from said shaftsuch that a plane defined by each of said blades is not parallel to saidcentral axis.
 3. The turbine of claim 1, further comprising anotherfastening sub-assembly, such that said fastening sub-assembly and saidanother fastening sub-assembly are designed to be disposed at oppositeends of said shaft and couple opposite ends of said substantiallycircularly arcing blades to said shaft.
 4. The turbine of claim 2,wherein each of said fastening sub-assembly and said another fasteningsub-assembly includes a hub plate having defined therein hub aperturessuch that said fasteners are designed to pass through said hubapertures.
 5. The turbine of claim 3, wherein each of said fasteningsub-assembly and said another fastening sub-assembly includes anauxiliary plate having defined therein auxiliary apertures such thatsaid fasteners are designed to pass through said auxiliary apertures. 6.The turbine of claim 4, wherein in an assembled configuration of saidturbine, each of opposite ends of said substantially circularly arcingblades is sandwiched between said corresponding hub plate and saidcorresponding auxiliary plate, and a first portion of each of saidfasteners is on one side of each of said substantially circularly arcingblades, and a second portion of each of said fasteners is on the otherside of each of said substantially circularly arcing blades.
 7. Theturbine of claim 5, wherein, in an assembled configuration of saidturbine, corresponding ones of said blade apertures, said hub aperturesand said auxiliary apertures align such that said fasteners fastencorresponding ones of said hub plate, said auxiliary plate and saidsubstantially circularly arcing blades.
 8. The turbine of claim 1,further comprising opposing shaft couplers for securely affixing each ofsaid fastening sub-assembly and said another fastening sub-assembly tosaid shaft.
 9. The turbine of claim 1, wherein each of saidsubstantially circularly arcing blades includes, along a substantiallength, an airfoil cross-section.
 10. The turbine of claim 1, wherein anangle between the plane defined by each of said substantially circularlyarcing blades and said central axis of said shaft is a value betweenabout 5 degrees and about 45 degrees.
 11. The turbine of claim 1,wherein said substantially circularly arcing blades are made from onematerial selected from a group consisting of composite, plastic andmetal.
 12. A power generating system, comprising a turbine, comprising acentral longitudinal shaft configured to rotate on a central axisperpendicular to a direction of fluid flow; a plurality of substantiallycircularly arcing blades designed to be coupled with said shaft, andeach of said substantially circularly arcing blades having defined atone end one or more blade apertures; a fastening sub-assembly includingfasteners and said fastening subassembly used for coupling saidsubstantially circularly arcing blades to said shaft; and wherein, in anassembled configuration of said turbine, a sweep of said arcing bladesdefines a substantially spherical shape when said arcing blades rotatewith said shaft, and when said fastening sub-assembly couples saidarcing blades to said shaft, said fasteners pass through said one ormore blade apertures; and a generator capable of being operativelycoupled to said shaft of said turbine and, during an operational stateof said power generating system, said generator generates power fromrotation of said turbine caused by a fluid impinging on said blades. 13.The power generating system of claim 12, wherein each end of saidsubstantially circularly arcing blades extends outwardly from said shaftsuch that a plane defined by each of said blades is not parallel to saidcentral axis.
 14. The power generating system of claim 12, wherein saidturbine further comprises another fastening sub-assembly, such that saidfastening sub-assembly and said another fastening sub-assembly aredesigned to be disposed at opposite ends of said shaft and coupleopposite ends of said substantially circularly arcing blades to saidshaft.
 15. The power generating system of claim 14, wherein each of saidfastening sub-assembly and said another fastening sub-assembly includesa hub plate having defined therein hub apertures such that saidfasteners are designed to pass through said hub apertures.
 16. The powergenerating system of claim 15, wherein each of said fasteningsub-assembly and said another fastening sub-assembly includes anauxiliary plate having defined therein auxiliary apertures such thatsaid fasteners are designed to pass through said auxiliary apertures.17. The power generating system of claim 16, wherein in an assembledconfiguration of said turbine, each of opposite ends of saidsubstantially circularly arcing blades is sandwiched between saidcorresponding hub plate and said corresponding auxiliary plate, and afirst portion of each of said fasteners is on one side of each of saidsubstantially circularly arcing blades, and a second portion of each ofsaid fasteners is on the other side of each of said substantiallycircularly arcing blades.
 18. The power generating system of claim 17,wherein, in an assembled configuration of said turbine, correspondingones of said blade apertures, said hub apertures and said auxiliaryapertures align such that said fasteners fasten corresponding ones ofsaid hub plate, said auxiliary plate and said substantially circularlyarcing blades.
 19. An electric power generating system, comprising aconduit for conveying a fluid; a turbine disposed inside said conduit,comprising a central longitudinal shaft configured to rotate on acentral axis perpendicular to a direction of fluid flow; a plurality ofsubstantially circularly arcing blades designed to be coupled with saidshaft, and each of said substantially circularly arcing blades havingdefined at one end one or more blade apertures; a fastening sub-assemblyincluding fasteners and said fastening subassembly used for couplingsaid substantially circularly arcing blades to said shaft; and wherein,in an assembled configuration of said turbine, a sweep of said arcingblades defines a substantially spherical shape when said arcing bladesrotate with said shaft, and when said fastening sub-assembly couplessaid arcing blades to said shaft, said fasteners pass through said oneor more blade apertures; and a generator capable of being operativelycoupled to said shaft of said turbine and, during an operational stateof said power generating system, said generator generates power fromrotation of said turbine caused by a fluid impinging on said blades. 20.The electric power generating system of claim 19, wherein the diameterof a cross section of said conduit is a value that is between about 12inches and about 144 inches.